1. Forestry

2. Forests Cover 1/3 of all land surface on earth In USA
80% = closed canopy
20% = open canopy
70% are in North America, Russian Federation, and South America
In USA
Largest land use category (1/3)
747 million acres (500 million non federal)
Timbering in Pacific Northwest employees 150,000 people; $7 billion per year industry

3. Forestry
Management of forests
Involves
Planting new trees
Fires

4. Ecological Services of Forests
Providing wildlife habitat
Carbon sinks
Affecting local climate patterns
Purifying air and water
Reducing soil erosion
Forests serves as a watershed, absorbing and releasing controlled amounts of water.
Providing energy and nutrient cycling

5. Old – Growth Forests
Forests that have not been seriously impacted by human activities
Rich in biodiversity
Depletion of old-growth forests increases the risk of climate change
Many have trees that have high economic value but take a long time to mature
Mahogany, oak, etc.

6. Characteristics of Old-Growth Forests
Older and mixed-age trees
Minimal signs of human activity
Multilayered canopy due to tree falls
Pit-and-mound topography due to trees falling and creating new microenvironments by recycling organic material into the local environment and providing habitat
Decaying wood and ground layer that provides a rich carbon sink

7. Characteristics of Old-Growth Forests cont.
Healthy soil profiles
Indicator species – species that can tell about the overall health of an ecosystem
Little vegetation on the forest floor due to light being a limiting factor

8. Old Growth Forest 22% of world’s forests

9. Secondary-Growth Forest 63% of worlds forests

10. Tree Plantations
Large, managed farms with uniformly aged trees of one species
Trees may or may not be native to the environment
Trees are used for pulp or lumber
Pine, spruce, eucalyptus
Harvested by clear cutting

11. Tree Plantations cont. Short rotation cycles
years temperate zones
6 – 10 years tropics
5% of worlds forests but give 20% of current world wood production
Leading to conversion of forests to tree plantations
May result in draining of wetlands and replacing of traditional hardwoods

12. Tree plantation characteristics
Do not support food webs
Contain little biodiversity
Decaying wood is absent
Use of fertilizers and pesticides can harm the environment

13. Tree plantation – new stuff
New techniques leave some natural forest with in the plantation to provide a wildlife corridor
The Kyoto Protocol encourages use of tree farms as a carbon sink
Carbon may be released after harvesting

14. Examples of Tree Farms

15. Tree plantations Pros Cons
Practical method for trees that requires full or moderate sunlight to grow
Efficient and economical method
Genetically improved species of trees resist disease and grow faster
Increases economic returns on investments
Produces a high yield of timber at the lowest cost, provides jobs
Cons
Reduces the recreational value of the land
Can cause soil erosion (on steep slopes), water pollution, flooding
Causes habitat fragmentation
Reduces biodiversity
Promotes monoculture
Tree plantations are prone to disease and infestation because of a lack of diversity

16. Forest Fires Important ecological features
Clear out old and dead trees making room for new growth
Some trees need fires to germinate – conifers
Wildfire frequency is increasing
4 times the average of 1970 – 1986
Total area burned is 7 times the previous levels
Forest Service lengthened the fire season by 78 days

17. Fire basics
Heat + Oxygen + Fuel source = Fire

18. Causes of Wildfire frequency changes
Climate change
changes in annual spring and summer temperatures
Longer, warmer summers
Early snow melt  earlier longer dry season
Changes in fire management philosophy
Old way: if there is a fire put it out NOW!
Lead to build up of flammable materials in the forest
New way: if fire is NOT threatening resources, let it burn

19. Types of Fires Crown Fire:
Occur in forests that have not had a burn for a long time
Extremely Hot
Burn Entire Trees – leap from tree top to tree top
Kills wildlife
Increase soil erosion
Destroys structures

20. Types of Fires Ground Fire: Occur underground
Burn partially decayed leaves
Common in peat bogs
Difficult to detect and extinguish

21. Types of Fires Surface Fire: Burns undergrowth and leaf litter
Kills seedlings and small trees
Spares older trees – most animals escape
Advantages:
Burns away ground material, reducing larger fires
Release minerals back into soil
Stimulates germination of some seeds
Helps keep pathogens and insects in check
Allows vegetation clearing for animals

22. Methods of fire control
Prevention:
Burning permits
Closing parts of forest during drought and high traffic
Educating the public
Prescribed burning: Purposely setting controlled surface fires to thin out underbrush
Burn out: letting large fires burn themselves out

23. Question: Who should pay to protect these homes?

24. Deforestation Conversion of forests into non forested areas
Natural: caused by tsunamis, forest fires, volcanic eruptions, glaciations, desertification
Human caused: land converted to
Livestock grazing
Grain fields
Mining
Petroleum extractions
Fuel wood cutting
Commercial logging
Tree plantations
Urban sprawl

26. Deforestation Results
Degraded environment
Reduced biodiversity
Reduced ecological services
Threatens loss of species with specialized niches
Decreases soil fertility
Reduces homes for migratory birds
Allows run-off into aquatic habitats
Changes in local climate patterns
Increases CO2 in the environment
Edge effects
Habitat fragmentation

27. Deforestation Results cont.
Alters hydrological cycle
Decreased amount of ground water
Increased flash flooding
Decreased evapotranspiration  less atmospheric moisture from rain
Loss of a carbon sink
Loss of tourist revenue

28. Causes of deforestation – schools of thought
Impoverished – believes that the major causes of deforestation is the growing number of poor people
Neoclassical – believes major cause is “open access property rights”
Political-ecological – believes major cause is entrepreneurs

29. Case Study: Hubbard Brook Experimental Forest
Centered on how deforestation affects nutrient cycles
Land: Forest with several watersheds each drained by a single creek, impervious bed rock close to the surface preventing seepage

30. Case Study: Hubbard Brook Experimental Forest

31. Case Study: Hubbard Brook Experimental Forest
Conclusions:
An undisturbed mature forest is a dynamic ecosystem
Inflow and outflow are balanced by nutrients entering and leaving the ecosystem
Deforestation lead to an increased water run-off
Nutrient loss could be limited by clearing forests in horizontal strips

32. Methods to manage and harvest trees
Even-age management: tree plantations
Uneven-age management: maintain a stand of trees from seedlings to mature trees
Selective cutting: specific trees are chosen and cut
High grading: cutting and removing only the largest and best trees
Shelterwood cutting: removes all mature trees in an area in a limited time

33. Methods to manage and harvest trees cont.
Seed Tree cutting: majority of trees removed except for scattered, seed producing trees used to regenerate a new strand
Clear-cutting: all of the trees in an area are cut at the same time. Sometimes used to cultivate shade-intolerant tree species
Strip cutting: clear-cutting a strip of trees that follows the land contour. The corridor is then allowed to regenerate

34. Forest Service
Established in 1905 as agency of US Department of Agriculture
155 national forests, 22 grasslands
Manages 193 million acres (about the size of Texas)
Used for: logging, farming, recreation, hunting, fishing, oil and gas extraction, watersheds, mining, livestock grazing, farming, and conservation

35. Forest Service Protects and manages natural resources
Provides community assistance
Cooperates with state and local governments, forest industries, and private land owners to mange resources
Provides international assistance in formulating policy and coordinating U.S. support for protection and management of world’s resources

36. Relevant Laws
Wilderness Act (1964): Created the legal definition of wilderness in the US. Currently 4 agencies (National Park Service, US Forest Service, US Fish and Wildlife service, and the Bureau of Land Management) are in charge of 106 million+ acres of federal wilderness
Wild and Scenic Rivers Act (1968): Preserves and protects certain rivers with outstanding natural, cultural, and recreational values in a free-flowing condition for the enjoyment of present and future generations. Classified rivers as wild, scenic, or recreational.

37. Assignment:
For each of the three schools of thought briefly design a management program to deal with deforestation based on the cause of deforestation for each school of thought.
Write these in your notes.